module spi_ee_config (			
								iRSTN,															
								iSPI_CLK,								
								iSPI_CLK_OUT,								
								iG_INT2,
								oDATA_L,
								oDATA_H,
								SPI_SDIO,
								oSPI_CSN,
								oSPI_CLK);

			
`include "spi_param.h"
	
//=======================================================
//  PORT declarations
//=======================================================
//	Host Side							
input					          iRSTN;
input					          iSPI_CLK, iSPI_CLK_OUT;
input					          iG_INT2;
output reg [SO_DataL:0] oDATA_L;
output reg [SO_DataL:0] oDATA_H;
//	SPI Side           
inout					          SPI_SDIO;
output					        oSPI_CSN;
output					        oSPI_CLK;       
                               
//=======================================================
//  REG/WIRE declarations
//=======================================================
reg	    [3:0] 	       ini_index;
reg		  [SI_DataL-2:0] write_data;
reg		  [SI_DataL:0]	 p2s_data;
reg                    spi_go;
wire                   spi_end;
wire	  [SO_DataL:0]	 s2p_data; 
reg     [SO_DataL:0]	 low_byte_data;
reg		       		       spi_state;
reg                    high_byte; // indicate to read the high or low byte
reg                    read_back; // indicate to read back data 
reg                    clear_status, read_ready;
reg     [3:0]          clear_status_d;
reg                    high_byte_d, read_back_d;
reg	    [IDLE_MSB:0]   read_idle_count; // reducing the reading rate

//=======================================================
//  Sub-module
//=======================================================
spi_controller u_spi_controller (		
							.iRSTN(iRSTN),
							.iSPI_CLK(iSPI_CLK),
							.iSPI_CLK_OUT(iSPI_CLK_OUT),
							.iP2S_DATA(p2s_data),
							.iSPI_GO(spi_go),
							.oSPI_END(spi_end),			
							.oS2P_DATA(s2p_data),			
							.SPI_SDIO(SPI_SDIO),
							.oSPI_CSN(oSPI_CSN),							
							.oSPI_CLK(oSPI_CLK));
							
//=======================================================
//  Structural coding
//=======================================================
// Initial Setting Table
always @ (ini_index)
	case (ini_index)
    0      : write_data = {THRESH_ACT,8'h20};
    1      : write_data = {THRESH_INACT,8'h03};
    2      : write_data = {TIME_INACT,8'h01};
    3      : write_data = {ACT_INACT_CTL,8'h7f};
    4      : write_data = {THRESH_FF,8'h09};
    5      : write_data = {TIME_FF,8'h46};
    6      : write_data = {BW_RATE,8'h09}; // output data rate : 50 Hz
    7      : write_data = {INT_ENABLE,8'h10};	
    8      : write_data = {INT_MAP,8'h10};
    9      : write_data = {DATA_FORMAT,8'h40};
	  default: write_data = {POWER_CONTROL,8'h08};
	endcase

always@(posedge iSPI_CLK or negedge iRSTN)
	if(!iRSTN)
	begin
		ini_index	<= 4'b0;
		spi_go		<= 1'b0;
		spi_state	<= IDLE;
		read_idle_count <= 0; // read mode only
		high_byte <= 1'b0; // read mode only
		read_back <= 1'b0; // read mode only
    clear_status <= 1'b0;
	end
	// initial setting (write mode)
	else if(ini_index < INI_NUMBER) 
		case(spi_state)
			IDLE : begin
					p2s_data  <= {WRITE_MODE, write_data};
					spi_go		<= 1'b1;
					spi_state	<= TRANSFER;
			end
			TRANSFER : begin
					if (spi_end)
					begin
		        ini_index	<= ini_index + 4'b1;
						spi_go		<= 1'b0;
						spi_state	<= IDLE;							
					end
			end
		endcase
  // read data and clear interrupt (read mode)
  else 
		case(spi_state)
			IDLE : begin
				  read_idle_count <= read_idle_count + 1'b1;
				
					if (high_byte) // multiple-byte read
				  begin
					  p2s_data[15:8] <= {READ_MODE, X_HB};						
					  read_back      <= 1'b1;
					end
				  else if (read_ready)
				  begin
					  p2s_data[15:8] <= {READ_MODE, X_LB};						
					  read_back      <= 1'b1;
					end
				  else if (!clear_status_d[3]&&iG_INT2 || read_idle_count[IDLE_MSB])
				  begin
					  p2s_data[15:8] <= {READ_MODE, INT_SOURCE};
					  clear_status   <= 1'b1;
          end

          if (high_byte || read_ready || read_idle_count[IDLE_MSB] || !clear_status_d[3]&&iG_INT2)
          begin
					  spi_go		<= 1'b1;
					  spi_state	<= TRANSFER;
					end

				  if (read_back_d) // update the read back data
				  begin
				  	if (high_byte_d)
				  	begin
				  	  oDATA_H <= s2p_data;	
				  	  oDATA_L <= low_byte_data;			  		
				  	end
				  	else
				  		low_byte_data <= s2p_data;
				  end
			end
			TRANSFER : begin
					if (spi_end)
					begin
						spi_go		<= 1'b0;
						spi_state	<= IDLE;
						
						if (read_back)
						begin
							read_back <= 1'b0;
					    high_byte <= !high_byte;
					    read_ready <= 1'b0;					
					  end
					  else
					  begin
              clear_status <= 1'b0;
              read_ready <= s2p_data[6];					  	
					    read_idle_count <= 0;
            end
					end
			end
		endcase
 
always@(posedge iSPI_CLK or negedge iRSTN)
	if(!iRSTN)
	begin
		high_byte_d <= 1'b0;
		read_back_d <= 1'b0;
		clear_status_d <= 4'b0;
	end
	else
	begin
		high_byte_d <= high_byte;
		read_back_d <= read_back;
		clear_status_d <= {clear_status_d[2:0], clear_status};
	end

endmodule					
